Arctic Basin Ecozone
The Arctic Basin Ecozone probably characterizes most peoples' impressions of Canada's Arctic. This ecozone, encompassing the permanent pack ice of the Arctic Ocean, stretches from the southern edge of the "approximate limit of polar ice" in the Beaufort Sea to the northern tip of Greenland. It also includes the Canadian Basin and the northern coast of Ellesmere Island. More than 90% of this region comprises a giant ice sheet that floats on the ocean, slowly rotating counterclockwise due to an ocean current called the Arctic Ocean Gyre.
The Arctic Basin Ecozone spans the most northerly areas of the Arctic. The climate is cold and dry, with winter temperatures as low as -35C, and summer temperatures rarely exceeding 5C. Mean annual precipitation ranges between 10 cm and 20 cm, although most of this remains trapped as part of the polar ice cap. As a result of cold temperatures, a lack of precipitation, and frequent high winds, life above the ice cap is sparse. However, beneath the thick ice, the ocean waters provide suitable habitat for numerous species.
The northern coast of Ellesmere Island is the only land area bordering the Arctic Basin Ecozone. As a result, this area is dominated by a deep ocean floor with only a small area of coastal shelf near the island. Under the ice and water, throughout most of the region, lies the Canadian Basin. This large, bowl-shaped hollow in the ocean floor averages 3600 m in depth. Its western fringe is bordered by the Mendeleyev Ridge, while its northern limit extends to the Alpha Ridge. These ridges are essentially underwater mountain ranges in the Arctic Ocean. Water in the depths of the Basin remains at a fairly constant temperature, unfrozen year-round. Here, deep below the protective ice cover, there is a diversity of organisms.
Vegetation in the Arctic Basin Ecozone must be very hardy to survive the permanent ice cover. Ice and the absence of tides prevent the mixing which would normally carry nutrients from the depths resulting in limited nutrient availability. In the summer, algae grow on the underside of the ice, despite the lack of nutrients, giving the ice a brownish appearance. At areas of open water, called polynyas, currents prevent ice formation and continually supply nutrients that allow algal blooms. Despite this, the total productivity of this ecozone is only 1% of the productivity of the Atlantic Ocean!

Nutrient and sunlight availability limits the amount of vegetation, which, in turn, limits wildlife diversity. However, many species are adapted to cold water and thrive throughout this region, including walruses, polar bears, belugas, narwhals, and several species of seals. These marine mammals have thick layers of blubber to keep their bodies warm as they swim in the icy waters feeding on fish, crustaceans, and zooplankton. One remarkable bird, the ivory gull, is actually able to live here year-round – a major accomplishment! It scavenges for anything it can find, including fish and marine mammal carcasses. Over 130 species of fish inhabit this ecozone. Many of the organisms in the Arctic Ocean are benthic invertebrates including anemones, clams, worms, sea stars, and sea spiders.